Recent research suggests that the frequency of antimicrobial resistance and its association with infectious diseases is increasing. Bacterial infections can occur in any subject, and many of such infections can be deadly. Nosocomial infections, for example, can be caused by strains of bacteria including deadly antimicrobial-resistant strains. In the United States alone, nosocomial infections are thought to contribute to or cause more than 77,000 deaths per year and cost approximately $5 to $10 billion annually. Among Gram-positive organisms, examples of resistant pathogens include resistant Staphylococcus aureus, β-lactam-resistant and multidrug-resistant pneumococci, and vancomycin-resistant enterococci. (Jones R N 2001 Chest 119 (supplement), 397S-404S: Resistance patterns among nosocomial pathogens: Trends over the past few years.)
The problem with bacterial infections and antibacterial resistance is compounded by the existence of bacterial strains resistant to multiple antibacterials. Thus, for at least this reason, there remains a need for new antimicrobials, particularly antimicrobials with different mechanisms of action.